CN108302476B

CN108302476B - Lighting device for a motor vehicle comprising a light guide

Info

Publication number: CN108302476B
Application number: CN201710914747.1A
Authority: CN
Inventors: 亚历山大·约尔格; 马瑞恩·库尔斯尔
Original assignee: Valeo Vision SAS
Current assignee: Valeo Vision SAS
Priority date: 2016-09-29
Filing date: 2017-09-29
Publication date: 2022-05-24
Anticipated expiration: 2037-09-29
Also published as: JP7023655B2; FR3056694A1; FR3056694B1; EP3301347A1; US10337684B2; JP2018078099A; CN114877286A; JP7274626B2; US20180087735A1; CN108302476A; JP2022065041A; EP3301347B1; EP3636990A1

Abstract

The invention relates to an optical lighting module (10) for a motor vehicle comprising a primary optical element (24) comprising: -a first rear portion (24A) comprising a plurality of longitudinal main axes of light guides (26A, 26B) arranged along at least one transverse row, each light guide comprising an exit front end surface (30A, 30B) for a secondary light beam; -a front portion (24B) having a common exit front surface (32) for the secondary light beams; characterized in that the front surface (32) of the front portion (24B) is configured to expand the secondary light beam at least in the vertical direction.

Description

Lighting device for a motor vehicle comprising a light guide

Technical Field

The invention relates to an optical lighting module for a motor vehicle comprising a main optical element, said main optical element comprising:

-a first rear portion comprising a plurality of longitudinal main axes of light guides arranged along at least one transverse row, each light guide comprising an exit front end surface for a secondary light beam;

a front portion having a common exit front surface for the secondary light beams.

Background

Optical lighting modules of this type are already known. They are able to emit longitudinally forward a final light beam, called "multi-beam" or even "pixel beam". The resulting beam projects an image of the primary light source matrix forward. By selectively switching each basic light source on or off, a final light beam can be generated that specifically illuminates certain areas of the road in front of the vehicle, while leaving other areas dark.

Such optical lighting modules are used in particular for generating adaptive lighting functions, also known by the acronym "ADB", "adaptive driving beam". Such ADB functionality aims to automatically detect road users who may be dazzled by the illumination light beam emitted by the headlamps in high beam mode, and to modify the profile of the illumination light beam so as to create dark zones where the detected user is located, while continuing to illuminate the road remotely on either side of the user. The ADB function provides a number of advantages: easy to use, better visibility than the illumination under the mode of passing light, greatly reduced dazzling risk, safe driving etc..

Such optical modules typically comprise a matrix of light sources, typically formed by Light Emitting Diodes (LEDs), a main optical element comprising a plurality of light guides and projection optics. The light emitting diodes are arranged on a planar printed circuit board, which extends in a plane orthogonal to the projection direction of the final light beam. The light guide of the primary optical element extends longitudinally from the light entrance surface to the light exit surface as a whole. The light guides are intended to shape the light rays emitted by the light emitting diodes into a relatively narrow light beam, the exit surface of each light guide forming a pixel. The exit surface of the light guide forms a matrix of elementary pixels imaged by the projection optics. Each pixel may be selectively illuminated by activation or deactivation of each light source.

Such a main optical element comprises a first row of first light guides intended to form rectangular shaped elementary pixels for illumination above a cut-off line.

Such a main optical element also comprises a second row of second light guides intended to form square-shaped elementary pixels for illumination below the cut-off line.

The image of square pixels will therefore illuminate roads near the vehicle, whereas the image of rectangular pixels will illuminate roads at greater distances.

An image of rectangular pixels may dazzle road users located at a short distance from the vehicle. Adaptive lighting involves detecting such road users and turning off the light sources forming pixels that may dazzle the users, while keeping the other light sources turned on to ensure good visibility to the vehicle driver.

For an optical lighting module that produces a final light beam that is comfortable for the driver, the image of the rectangular pixels vertically overlaps the image of the square pixels. It has been found that driver comfort is enhanced when the image of the rectangular pixels extends vertically over 5 °.

Now, at present, a single light conduction cannot achieve such a vertical range of rectangular pixels while remaining relatively narrow laterally.

Furthermore, it was found that better visual comfort is obtained when the square pixels have a dimmed bottom side.

Furthermore, the visually pleasing illumination beam must also illuminate the underside of the road. Now, even by changing the shape of the light guides arranged at the lateral ends of the main optical element, the pixels created by the lateral end light guides are not wide enough to adequately illuminate one side of the road.

Disclosure of Invention

It is an object of the present invention to present an optical lighting module capable of generating a pixel light beam or "pixel beam" capable of comfortably lighting a road.

The invention therefore relates to an optical lighting module of the aforementioned type, characterized in that the front surface of the front portion is configured to spread the secondary light beam at least in the vertical direction.

According to other features of the invention:

the exit surface of the front part of the main optical element has at least one lateral vertical end bar curved around a lateral axis to vertically expand the secondary light beams emitted by the light guides of the relevant row;

the optical module comprises at least two parallel transverse rows of light guides, the exit surface of the front portion of the main optical element having two transverse vertical end bars, respectively curved about a transverse axis to vertically expand the secondary light beams emitted by the light guides of the relevant row;

the exit surface of the front portion comprises a central strip extending vertically between two vertical end strips and having a vertical straight form in a longitudinal vertical cross-section;

at least one lateral end of the exit surface of the front portion has a curvature about a vertical axis to laterally expand the secondary light beams emitted by the respective end light guides of each row;

the two lateral ends of the exit surface of the front portion each have a curvature about a vertical axis to laterally expand the secondary light beams emitted by the respective end light guides of each row;

-a central portion of the exit surface of the front portion extending between the two lateral ends has the shape of a semicircular cylinder.

-the central portion extends in opposite directions to the light guides of each row, except for the two end light guides;

each light emitting diode is associated with a light guide;

the optical module is capable of emitting a light beam that produces an adaptive lighting function.

The invention also relates to a motor vehicle lighting device comprising a module produced according to the teachings of the invention.

The lighting device further comprises a low beam module.

Drawings

Other features and advantages of the invention will become apparent upon reading the following detailed description, with reference to the accompanying drawings, in which:

figure 1 is a perspective view showing an optical lighting module produced according to the teachings of the present invention;

fig. 2 is a perspective view showing the printed circuit board of the optical module of fig. 1 comprising a matrix of light emitting diodes.

Figure 3 is a perspective view showing the rear of the main optical element of the optical module of figure 1 comprising a plurality of light guides;

FIG. 4 is a cross-sectional view along the horizontal cutting plane 4-4 of FIG. 1;

fig. 5 is a vertical section along the cutting plane 5-5 of fig. 6, showing the main optical element equipped with a convex exit front surface capable of vertically expanding the secondary light beam;

fig. 6 is a transverse cross-sectional view along the cutting plane 6-6 of fig. 5, showing the main optical element equipped with a convex exit front surface capable of transversely expanding the secondary light beams emitted by the end light guides of each row.

Detailed Description

In the following description, the following orientations will be used in a non-limiting manner:

-a longitudinal direction "L" oriented from back to front along the optical axis of the projection optics of the optical module;

-a transverse "T", oriented from left to right;

vertical "V", oriented from bottom to top.

The vertical direction "V" is used as a geometric reference independent of the direction of gravity.

In the following description, elements having the same structure and/or similar functions will be denoted by the same reference numerals.

Fig. 1 shows an optical lighting module 10 for a motor vehicle, which optical lighting module 10 is intended to emit a final light beam longitudinally forward. The final beam is here an adaptive beam, which consists of a plurality of basic beams that overlap. Such an optical lighting module 10 is in particular capable of realizing an adaptive high beam function, also known by the acronym "ADB", of an "adaptive driving beam", or also of realizing a directional lighting beam function, also known by the acronym "DBL", of a "dynamic bending lamp".

The optical module 10 is intended to equip a front lighting device of a motor vehicle. The front lighting device also comprises a second optical module intended to emit a single low-beam light beam having a cut-off line.

The optical lighting module 10 mainly comprises a light emitting device 12 and projection optics 14, the projection optics 14 being arranged longitudinally in front of the light emitting device 12 and remote from the light emitting device 12. Projection optics 14 has a longitudinal optical axis "a".

As shown in fig. 2, the light-emitting means 12 here comprise a matrix 16 of primary elementary light sources 18. Here, the light source is a light emitting diode 18. The matrix 16 is provided with at least two transverse rows of seventeen light emitting diodes 18, here two rows. The optical axis "a" passes substantially through the middle of the matrix 16 in the lateral direction. All the light emitting diodes 18 of the matrix have the same size of the illuminating surface. Here, they are square illumination surfaces.

The matrix 16 extends in a plane orthogonal to the longitudinal direction "L". More specifically, the light emitting diodes 18 are supported here by the front surface of the printed circuit board 20.

These leds 18 may generate heat during operation. Accordingly, a heat sink 22 including a heat sink is attached to the rear surface of the printed circuit board 20 to discharge heat.

The light emitting diode 18 emits light in a very open cone of light. In the example shown in fig. 5, the aperture angle is 180 °. A primary optical element 24 is arranged longitudinally in front of the matrix 16 of light emitting diodes 18 to modify the distribution of the emitted light.

As shown in fig. 3, the main optical element 24 here comprises a first rear portion 24A formed by a plurality of light guides 26A, 26B. Each

light guide

26A, 26B extends along a longitudinal main axis from an

entrance surface

28A, 28B to an exit

front end surface

30A, 30B for light rays, as can be seen in particular in fig. 4 and 5. Each

light guide

26A, 26B is designed to guide light entering through the

entrance surface

28A, 28B to the

exit surface

30A, 30B. Each

exit surface

30A, 30B forms a pixel that can be selectively turned on by individual control of each light emitting diode 18.

The rear portion 24A comprises a matrix comprising at least the same number of light guides 26A, 26B as the number of light emitting diodes 18 comprised by the matrix 16. Each light emitting diode 18 is associated with a

light guide

26A, 26B. Thus, the rear portion 24A includes at least two rows of seventeen

light guides

26A, 26B.

The entrance surfaces 28A, 28B of the light guides 26A, 26B are arranged in a common plane parallel to the plane of the printed circuit board 20. When the primary optical element 24 is arranged in the optical module 10, as shown in fig. 4, each

incident surface

28A, 28B is thus longitudinally positioned facing and adjacent to the associated light emitting diode 18, so that a majority of the light rays emitted by each light emitting diode 18 enter the associated

light guide

26A, 26B.

As shown in fig. 3, each

light guide

26A, 26B may have the following portions: this section is adapted to generate an outgoing secondary elementary beam (outgoing secondary elementary light beam) of the form required for the function of the optical lighting module 10. Each secondary elementary beam has a smaller aperture angle than the aperture angle of the light source 18.

As shown, the primary optical element 24 includes two transverse rows of light guides. The bottom first row of light guides will be indicated by reference numeral 26A, while the top second row of light guides will be indicated by reference numeral 26B.

A first type of light guide 26A (hereinafter "first light guide 26A") occupies the bottom row. They are intended to form highly elongated pixels. More specifically, the elongated pixels have an overall rectangular shape with a length extending vertically. For this purpose, the exit surface 30A of the first light guide 26A has a corresponding rectangular shape.

A second type of light guide 26B (hereinafter "second light guide 26B") occupies the top row. They are intended to form pixels of shorter height compared to the elongated pixels. More specifically, the short pixels have an overall square shape. For this purpose, the exit surface 30B of the second light guide 26B has a corresponding square shape.

For each of the light guides 26A, 26B, the exit surfaces 30A, 30B have a profile of similar form to the entrance surfaces 28A, 28B. Thus, the entrance surface 28A of the first light guide 26A has a rectangular profile. Similarly, the entrance surface 28B of the second light guide 26B has a square profile.

As mentioned in the preamble, the image of rectangular shaped pixels is intended to vertically overlap the image of square shaped pixels. To this end, each first light guide 26A is associated with a parallel second light guide 26B, the second light guides 26B being arranged near and just near the top edge of said associated first light guide 26A.

As shown in fig. 4, the exit surfaces 30A, 30B of the light guides 26A, 26B are arranged in a common emission plane "P" that is parallel to the plane of the printed circuit board 20. In this way, both light guides 26A, 26B have the same length.

Thus, the exit surfaces 30A, 30B of the light guides 26A, 26B form a matrix, here seventeen exit surfaces 30A of the first light guide 26A of the first row and seventeen exit surfaces 30B of the second light guide 26B of the second row. Each of the exit surfaces 30A, 30B is capable of emitting a secondary elementary light beam in the longitudinal main direction of projection from a common emission plane "P" perpendicular to the longitudinal direction "L". The exit surfaces 30A, 30B are arranged in close proximity to each other, for example at a spacing of 0.1 mm.

The main optical element 24 further comprises a front portion 24B for forming a secondary primary light beam emitted by the primary light source 30.

The front portion 24B comprises a common exit front end surface 32 for the light rays of the primary optical element.

This front portion 24B is here made in a single piece with the light guides 26A, 26B so as to form the main optical element 24 in the form of a block.

The primary optical element 24 is made, for example, of silicon, polycarbonate, polymethyl methacrylate (PMMA) or any other material suitable for producing the light guides 26A, 26B.

As a variant, the primary optical element 24 produced according to the teachings of the present invention is made of silicon.

The exit front surface 32 of the front portion 24B is configured to expand the secondary primary light beam vertically and/or horizontally.

The front surface 32 has an overall rectangular-shaped profile with a length extending transversely and parallel to the rows of

light guides

26A, 26B and a width extending vertically. Thus, the front surface 32 is vertically bounded by a bottom lateral edge 36A and a top lateral edge 36B. The front surface 32 may also be laterally delimited by two vertical edges 37.

In the following, as shown in fig. 5, a distinction will be made between a bottom region 32A of the front surface 32, which is intended to receive the secondary light beams emitted by the bottom row of light guides 26A, and a top region 32B of the front surface 32, which top region 32B is intended to receive the secondary light beams emitted by the top row of light guides 26B.

According to a first aspect of the invention, the front surface 32 of the front portion 24B is configured to expand the secondary light beam at least in the vertical direction.

To this end, the exit surface 32 of the front portion 24B of the main optical element has at least one lateral

vertical end bar

38A, 38B, which lateral

vertical end bar

38A, 38B is curved about a lateral axis to vertically expand the secondary light beams emitted by the row of light guides 26A, 26B associated with this

end bar

38A, 38B. Thus, said lateral end strips 38A, 38B of the exit surface 32 have a convex shape.

In the example shown in fig. 5, the primary optical element 24 comprises two parallel transverse rows of

light guides

26A, 26B. To allow vertical expansion of the light beams emitted by the light guides 26A, 26B of each of the two rows, the two lateral end bars, which vertically delimit the exit surface 32 of the front portion 24B of the primary optical element, are respectively bent around a lateral axis to vertically expand the secondary light beams emitted by the light guides 26A, 26B of each associated row.

More specifically, the bottom region 32A has a bottom end strip 38A that abuts a bottom edge 36A of the front surface 32. The bottom end bar 38A has a convex progressive curvature configured to vertically spread the rays so as to form a beam that extends vertically over 5 °. To this end, in vertical longitudinal section, the curvature of the bottom end strip 38A has a tangent that forms an angle of less than 45 ° overall over most of the curvature. Thus, the light is deflected slightly downward by refraction through the bottom end bar 38A. However, the secondary light beams emitted by each of the associated light guides 26A and exiting through the surface 32 have a relatively sharp bottom limit.

It will be appreciated that the invention is not limited to this particular curvature and that the curvature will be able to be adapted according to the required expansion of the light.

The top region 32B has a top end strip 38B contiguous with the top edge 36B of the front surface 32. The top end bar 38B has a convex curvature with a radius of curvature that is more pronounced than the curvature of the bottom end bar 38A so that the secondary beam forms a pixel with an upper limit of blurring. To this end, in vertical longitudinal cross-section, the curvature of the top end strip 38B has a tangent that forms an angle that is greater than 45 ° overall over most of the curvature. Thus, by refraction through the top end bar 38B, the rays at the top of the secondary beam are deflected upwards by a very significant angle. Thus, the secondary light beams emitted by each of the associated light guides 26B and exiting through the surface 32 have an upper limit of ambiguity.

For the portion of the secondary beam that overlaps to have a sharp limit, the exit surface 32 of the front portion 24B includes a central strip 40 extending vertically between the top and bottom end strips 38A, 38B. The center bar 40 has a linear shape in a longitudinal vertical cross section.

As a variant, the height of the central strip can be adapted.

According to another variant of the invention, the exit surface does not comprise a central strip. Thus, the two curved strips are directly connected to each other without interposing a central strip.

Furthermore, in order to make it possible to laterally expand the secondary light beams emitted by the end light guides 26A, 26B (which are located on the sides of the passages of each row), at least one lateral end vertical portion 42 of the exit surface 32 of the front portion 24B has a curvature about a vertical axis to expand the secondary light beams emitted by the respective end light guides 26A, 26B of each row in a lateral direction. For this purpose, the vertical portion 42 has a convex shape in longitudinal transverse section.

In the example shown in the figures, the same main optical element 24 is advantageously intended to equip the vehicle independently of the mounting side, on the left or right side.

In order to make it possible to fit the same body element 24 to both sides of the installation, the two lateral vertical ends 42 of the exit surface 32 of the front portion 24B each have a curvature about a vertical axis to expand the secondary light beams emitted by the respective end light guides of each row in opposite lateral directions.

As a variant, the exit surface has only a single curved end, the other curved end being eliminated. Referring to fig. 6, one of the ends 42 of the optical module is then eliminated. Thus, the optical module comprises an exit surface which is asymmetric with respect to the vertical longitudinal mid-plane. In this case, a different main optical module is arranged on each side of the vehicle.

The vertical end strips 38A, 38B overlap the lateral end portions 42. Thus, both end portions 42 have a curvature about both the lateral axis and about the vertical axis. In other words, the transverse end 42 has a spherical shape. In this way, the secondary light beams emitted by the end light guides 26A, 26B are vertically and laterally expanded to form a mask-like light distribution.

Instead, the secondary light beam emitted by the other

light guide

26A, 26B is intended to spread in the vertical direction only through the exit surface 32. The central portion 44 of the exit surface extends in the opposite direction to the light guides 26A, 26B of each row except for the two end light guides. In this regard, the intermediate portion 44 of the exit surface 32 of the front portion 24B extending between the two lateral ends 42 has a semi-cylindrical shape. Semi-cylindrical is understood to mean that the central portion 44 of the exit front surface 32 is produced by a displacement of a transverse straight line along an open curve formed by the vertical contour of the three

transverse strips

38A, 38B, 40, as shown in fig. 5. Therefore, the exit surface 32 has a smooth appearance. As a variant not shown, the exit surface may also be partially embossed.

Furthermore, the projection optics 14 are arranged longitudinally in front of and away from the emission plane "P". The projection optics 14 are capable of projecting an image of the exit surfaces 30A, 30B to infinity to form a final light beam. When projected onto a laterally vertical screen (not shown) located at a large distance, for example 25m, each

illuminated exit surface

30A, 30B makes it possible to illuminate an area of the screen. These areas overlap slightly to emit light uniformly. Each diode 18 is controlled independently so that each area of the screen can be selectively illuminated.

The projection optics 14 are here manufactured as a single piece.

As is known, the projection optics 14 include an object focal plane "S" and extend generally perpendicular to an optical axis "a" that intersects the object focal plane "S" at an object focal point.

For the resulting light beam to have the desired light characteristics, the exit surfaces 30A, 30B must be imaged in a substantially sharp manner. For this purpose, each elementary light source 30 is located in the object focal plane of the projection optics 14.

In theory, the projection optics 14 should have an object focal plane that is flat and perfectly orthogonal to the optical axis "A". In practice, however, the projection optics 14 are known to have an object focal surface with concave spherical curvature imperfections. This defect is known as the Petzval field aberration.

In order to be able to correctly focus the projection optics 14 on the primary light source 30, a secondary field correction optical element 34 is inserted between the emission plane "P" and the projection optics 14. The field correction optical element 34 is dedicated to correcting field curvature aberrations of the projection optics 14. The field correcting optical element 34 is formed by at least one field correcting lens, also referred to as a "field flatness lens". In the example shown in the figure, the field correcting optical element 34 comprises a single field correcting lens and will therefore be denoted 34.

It should be noted that the entrance surfaces 28A, 28B of the two

light guides

26A, 26B located at the lateral ends are not arranged in the same vertical lateral plane. The

surfaces

28A, 28B are arranged, for example, around a fan of leds. This makes it possible to participate in the expansion of the light beam in the lateral direction.

Claims

1. An optical lighting module (10) for a motor vehicle comprising a primary optical element (24), the primary optical element comprising:

-a first rear portion (24A) comprising a plurality of longitudinal main axes of light guides (26A, 26B) arranged along at least one transverse row, each light guide comprising an exit front end surface (30A, 30B) for a secondary light beam;

-a front portion (24B) having a common exit front surface (32) for the secondary light beams;

characterized in that the exit front surface (32) of the front part (24B) is configured to expand the secondary light beam at least in the vertical direction,

the first rear portion (24A) comprises at least two parallel transverse rows of light guides (26A, 26B), the exit front surface (32) of the front portion (24B) of the main optical element (24) having two transverse vertical end bars (38A, 38B), each transverse vertical end bar (38A, 38B) being curved about a transverse axis to vertically expand the secondary light beams emitted by the associated row of light guides (26A, 26B).

2. The optical lighting module (10) as claimed in the preceding claim, characterized in that the exit front surface (32) of the front section (24B) comprises a central strip (40), which central strip (40) extends vertically between the two vertical end strips (38A, 38B) and has the form of a vertical straight line in longitudinal vertical section.

3. The optical lighting module (10) according to any one of the preceding claims, characterized in that at least one lateral end (42) of the front exit front surface (32) has a curvature about a vertical axis to laterally expand the secondary light beams emitted by the respective end light guides (26A, 26B) of each row.

4. The optical lighting module (10) according to claim 3, characterized in that the two lateral ends (42) of the exit front surface (32) of the front portion (24B) each have a curvature about a vertical axis to laterally spread the secondary light beams emitted by the respective end light guides (26A, 26B) of each row.

5. The optical lighting module (10) according to claim 1 or 2, characterized in that a central portion (44) of the exit front surface (32) of the front portion (24B) extending between two lateral ends (42) has the shape of a semicircular cylinder.

6. The optical lighting module (10) according to claim 5, characterized in that the central portion (44) extends in opposite direction to the light guides (26A, 26B) of each row, except for the two end light guides (26A, 26B).

7. The optical lighting module (10) according to claim 1 or 2, characterized in that each light emitting diode (18) is associated with a light guide (26A, 26B).

8. The optical lighting module (10) according to claim 1 or 2, characterized in that the optical lighting module (10) is capable of emitting a light beam that produces an adaptive lighting function.

9. An automotive lighting device comprising the optical lighting module according to any one of claims 1 to 8.

10. The automotive lighting device of claim 9, further comprising a low beam module.